A determination of a constituent of a liquid sample flowing in a stream may be carried out using a variety of methods and techniques. A significant number of methods and analysis techniques rely on interrogating the liquid sample using optical means. Optical means is where a beam of light, or other electromagnetic radiation, is transmitted through the liquid and the light is either absorbed or scattered or the light stimulates fluorescence in proportion to a determinable component of the liquid, analyte, or contaminate of interest.
Entrained air and other gases present within the liquid sample can cause a portion of the light beam to scatter as the light travels through the liquid sample resulting in a reduced transmission of the light through the liquid sample. Entrained air and other gases also increase an observability of the beam within the liquid. The decrease in the transmission of light through the liquid sample due to entrained air mimics absorption and is indistinguishable from that which is due to an analyte. The observability of the beam due to entrained air likewise interferes with nephelometric or fluorometric determination methods as more light is scattered than can be accounted due to particle content or fluorescence of the liquid sample.
It is therefore important for an accurate determination of a constituent of a liquid that air or other entrained gases be removed prior to interrogation of the liquid sample by a beam of light. More specifically, air or other entrained gases should be (i) removed to the extent that the remaining air or gases have no significant contribution to a limit of detection of the method of analysis, and/or (ii) reduced to less than that which does not interfere with a determinable property of the liquid.